Brain dysfunction can be acute or chronic. Acute brain dysfunction is generally caused by alcohol or drug intoxication, extreme fatigue, medical conditions such as cerebrovascular accidents, and sports and work-related concussions, as well as other conditions, including Post-Traumatic Stress Disorder (PTSD). Chronic brain dysfunction is medically related to age-related dementia, cerebral arteriosclerosis, Alzheimer's disease, Parkinson's disease, brain tumors, and other neurological and/or genetic disease entities.
Chronic brain dysfunction can also result from concussions, especially if these are repetitive. In some cases it has been postulated that PTSD may be related to an end product of the concussive effects of explosive devices, such as Improvised Explosive Devices (IED), at near range (although other causes are also postulated).
According to the U.S. Department of Veterans Affairs Center for PTSD, Defense and Veterans Brain Injury Center, and the Centers for Disease Control and Prevention:
Since 2011, more than 276,000 U.S. troops suffered some form of traumatic brain injury. PTSD occurs in 11-20% of veterans of the Iraq and Afghanistan wars, and was noted in some 30% of Viet Nam veterans.
Gaze-tracking deficiencies are known to be related to brain dysfunction. For example, when a highway patrolman asks a motorist suspected of impairment from drugs or alcohol to follow the officer's finger, this is an example of a method, albeit a crude and subjective one, for testing gaze tracking Gaze tracking deficiencies may also be related to glaucoma and other medical conditions.
Kasha and Massengill et al., have disclosed that errors in gaze tracking can be related to “fatigue”—but never in a sophisticated way, and neither suggests using sophisticated comparison techniques. Therefore, neither Kasha nor Massengill et al. disclose how fatigue can be objectively and accurately measured.
This Background is provided to introduce a brief context for the Summary and Detailed Description that follow. This Background is not intended to be an aid in determining the scope of the claimed subject matter, nor to be viewed as limiting the claimed subject matter to implementations that solve any or all of the disadvantages or problems presented above.